Revert "Utilise variable for custom locations proxy_pass"

This reverts commit 6c1ae77.

Author: Julian Reinhardt

backend/templates/_location.conf

@@ -1,11 +1,10 @@
   location {{ path }} {
-    set              $upstream {{ forward_scheme }}://{{ forward_host }}:{{ forward_port }}{{ forward_path }};
     proxy_set_header Host $host;
     proxy_set_header X-Forwarded-Scheme $scheme;
     proxy_set_header X-Forwarded-Proto  $scheme;
     proxy_set_header X-Forwarded-For    $remote_addr;
     proxy_set_header X-Real-IP		$remote_addr;
-    proxy_pass       $upstream;
+    proxy_pass       {{ forward_scheme }}://{{ forward_host }}:{{ forward_port }}{{ forward_path }};
 
     {% if access_list_id > 0 %}
     {% if access_list.items.length > 0 %}